Organ walls are composed of several layers: the mucosa (surface layer), the submucosa, the muscularis (muscle layer) and the serosa (connective tissue layer). A variety of lesions comprising dead, diseased or abnormal tissue may form on the mucosal walls of the colon, esophagus, stomach and duodenum. For example, gastrointestinal, colonic and esophageal cancers may form within the mucosal layer and manifest as a polyp or tissue mass that extends into the lumen of the respective organ.
Endoscopic mucosal resection (EMR) is a minimally invasive technique by which cancerous or otherwise abnormal tissues are resected without disrupting the integrity of the organ wall. EMR is generally performed using an endoscope that includes a long narrow tube equipped with a light, video camera and one or more channels to receive a variety of medical instruments. During an EMR procedure, the endoscope is passed down the esophagus or guided through the rectum to the site of a cancerous or abnormal tissue within the mucosal wall of the target organ. The distal end of the endoscope is equipped with an endoscopic hood that is positioned over the tissue to be resected. Once properly positioned, suction is applied to the endoscope to draw the target tissue into the endoscopic hood, where it is then resected using a variety of techniques known in the art. The excised tissue is then extracted from the endoscope for examination and/or disposal.
Currently available EMR systems use suction to draw the target tissue into the endoscopic hood and deploy an elastic band around the base of the resulting pseudo-polyp. The suction is then released and the EMR hood and endoscope are pulled proximally to free the pseudo-polyp. A resection snare is passed through the working channel of the endoscope and manipulated to capture and resect the pseudo-polyp from the surrounding tissue. Once freed, the resected tissue is recaptured within the EMR hood using suction, or by introducing a separate grasping element (i.e., basket, forceps etc.) through the endoscope working channel. As multiple elastic bands are provided with such devices, several resections may be performed using the same EMR hood.
Other EMR systems do not require elastic bands to create the pseudo-polyp. Instead, a snare is deployed around the inside of the EMR hood so that the tissue can be resected immediately following formation of the pseudo-polyp. A major drawback of this system, however, is the minimal recovery afforded by the snare once the resection has been performed. This requires a new snare to be inserted and deployed within the EMR hood for each subsequent tissue resection.
Although the EMR systems described above use different techniques to form and resect the pseudo-polyp, they are similar in that both require multiple users to simultaneously control the endoscope and resection snare. In a typical EMR procedure the endoscope is controlled/maneuvered by a physician while the snaring/resecting steps are performed by a nurse. For example, when the physician has determined that the target tissue is properly positioned within the EMR hood, he/she must instruct the nurse to tighten the snare around the pseudo-polyp, followed by an instruction to apply cauterization energy. Once the target tissue is fully resected, the physician then instructs the nurse to cease cauterization and retract the snare. As one might expect, this process limits the physician's tactile sense for the procedure and requires a significant amount of communication with the nurse. This disclosure is related to an EMR hood that allows the physician to create and resect a pseudo-polyp in a single step without the need for additional assistance.